Similan Islands - Bluewater Dive Travel

Similan Islands

Similan Islands Diving
A coral reef at a dive site in the Similan Islands
Anemone fish at a Similan Islands dive site.
A turtle seen while scuba diving the Similan Islands
Similan Islands coral reef
A peacock mantis shrimp seen diving the Similan Islands
Similan Islands Liveaboard
Scuba Diving in the Similan Islands
Similan Islands reef life

Similan Islands, Thailand

intro to the Similan islands

Scuba diving the Similan Islands has got to be the highlight of any dive trip to Thailand, and for good reason. One of the best dive spots in Southeast Asia, the protected islands attract divers from around the world to explore its rich and diverse waters. A dive trip to the Similan Islands will be one you won't forget!


The plentiful marine life of the Andaman Sea is showcased in all its glory on a Similan Islands liveaboard trip. Comfortably warm waters and mild currents make for dream-like conditions, where large pelagics are often spotted feeding above the bountiful reefs. 

Interested in diving the Similan Islands? You may want to check out the Andaman Islands.




These world-famous islands stretch north-south in the Andaman Sea, 30 miles off the coast of southern Thailand. Covering an area of approximately 87 square miles, the nine islands of the archipelago, plus Ko Bon and Ko Tachai to the north, make up the Mu Ko Similan National Park

The real draw here is the manta rays and whale sharks that visit the warm waters from December until April each year. Outside these months diving is still spectacular, however, with medium-sized species patrolling the bustling reefs, and plentiful macro hiding amongst the beautiful hard corals. Liveaboards in Similan Islands really do offer an amazing scuba diving experience.

Thailand  Thailand



The Similan Islands National Park was closed to tourists in October 2016 due to the impact of huge numbers of day-trippers, but reopened two years later and has a current cap of 3,325 visitors per day. All tourist accommodation on the islands is now closed, except for a few park-managed tents and bungalows. In addition, access to three of the islands is restricted to protect nesting turtles, and one is privately owned. As such, a Similan Islands liveaboard is the most comfortable, and by far the most convenient way to access all these intriguing islands have to offer.

For a similar liveaboard experience closer to home, check out our Caribbean liveaboards.

New to liveaboards? Check out our guide to the World of Liveaboard Diving.


Diving Information 

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Most of Southeast Asia’s extensive marine catalog can be found in the waters around the Similan Islands. The region’s impressive corals were declared ‘fully recovered’ by the national park authorities in 2019, and the diversity of species living on the vibrant reefs only confirms this.

Interested in corals? Check out our list of the Best Coral Reefs in the World.
Thailand Reef  Thailand Reef
A good number of shark species can be found, including blacktip and whitetip reef sharks, zebra sharks, and leopard sharks. Blue-spotted ribbon tail rays and spotted eagle rays can often be seen sweeping across the sand, and schools of barracuda, giant trevally, and Napoleon wrasse are all regular visitors.
Four species of marine turtles live in the waters around the Similan Islands, with the beaches of Ko Huyong, Ko Payang, and Ko Payan (also referred to as Islands 1, 2, and 3) recognized as crucial turtle nesting sites for the leatherback and olive ridley turtles. Divers will often be accompanied by green or hawksbill turtles when they explore the outlying atolls.
The critter-life is no less exciting, with multicolored nudibranchs, pipefish, scorpionfish, and tiny octopus contributing to the rich macro scene. 

Interested in macro? Check out our list of the Best Macro Destinations in the World.

Thailand Mantis Thailand Nudibranch Thailand Seahorse

Between December and April each year, manta rays and whale sharks stop-off on their migration to feed in the Andaman Sea’s plankton-rich waters. Individuals will often stick around for several weeks, and can regularly be sighted around the outer reefs and atolls.

Whale Shark Manta Thailand
The fascinating underwater topography of these islands creates an ethereal backdrop to an exotic aquarium, where granite columns and stacks appear almost fluid in structure, shimmering and melting in the dazzling sunlight that pierces the crystal water. Diving the Similan Islands is a real treat, and one of the most unique and rewarding liveaboards trips you can experience.
Check out Raja Ampat scuba diving for some other great liveaboard trips.

Diving Conditions

  • Water temperature: 83-87°F (28-30°C) year-round.
  • Visibility: Excellent, up to 150ft.
  • Depth Range: Most dives are less than 100ft.
  • Diving Difficulty: There is a range of sites suitable for all levels, and many dives are easy and quite shallow.



Similan islands best diving spots  

The top best dive sites in the Similan Islands. Pick a dive spot or read the entire list:

1. Richelieu Rock

2. Koh Tachai Pinnacle 

3. Ko Bon West 

4. Christmas Point

5. Donald Duck Bay

6. Elephant Head Rock

7. West of Eden & Deep Six

8. Shark Fin Reef & Boulder City




Fifty-five miles north of the Similan Islands, the lonely pinnacle of Richelieu Rock attracts a wealth of marine life to its spectacular corals. This site is regarded as the best dive in Thailand, due to the great diversity of marine life appearing in vast numbers. The rock’s isolated location makes it a magnet for pelagic giants such as whale sharks and mantas, as well as tuna, barracuda, trevally, and turtles. Schooling snapper and glassfish create a constant ebb and flow of movement above the dense coral reefs, which in turn hide octopus, squid, moray eels, and some superb macro.

Find out why we think Richelieu Rock is one of the world's best dive sites.


In the furthest reaches of the national park, Koh Tachai Pinnacle is an exciting and challenging site best suited to intermediate and experienced divers. The dive centers around an open-ocean pinnacle and is the best place to spot passing mantas and whale sharks, as well as barracuda and trevally hunting above the granite rocks.

3. KO BON WEST, KO BON (Island 10)

This island’s limestone walls are coated in a patchwork of colorful soft corals, and a myriad of macro can be found sheltering from strong currents in the cracks and crevices. Ko Bon West is a favorite cleaning station for manta rays, who visit in the late afternoon to rid themselves of pesky parasites.


Located on the northwest edge of Ko Bangu, a collection of large boulders and quirky rock formations create exciting swim-throughs and tunnels in an incredibly scenic dive. The rocks are covered in soft corals and sea fans, and a coral garden of immense pore and staghorn corals can be found in the shallower waters. Expect to see the resident school of bluefin trevally, giant sweetlips and grouper in the swim-throughs, and firey goby amongst the coral.


This is a great macro site on the main island, and the shallow bay offers up some fascinating critters around a comically-shaped rock. Especially good for night dives, expect to spot plenty of octopus and cuttlefish as well as any number of crabs, shrimps, and other crustaceans.


Sitting around a mile offshore, the ocean swell and currents around Elephant Head Rock make it another site suited to more experienced divers. The dive itself is a fascinating maze of boulders and caverns, creating hiding places for all manner of species from curious moray eels, to boxer shrimp, octopus, and the spectacular yet sinister lionfish.


These two sites merge at the northwestern tip of Ko Bayu and are perhaps the most iconic of the Similan Islands’ dive sites. Showcasing the rich and diverse marine life of the Andaman Sea, West of Eden’s large boulders are covered in sea fans, beautiful anemones, feather stars, tube sponges, and soft coral. This gives way to the sloping reef and deeper walls of Deep Six, where pinnacles and rock clusters create a stunning backdrop. Expect to spot rays, moray eels and turtles, pelagics such as dogtooth tuna and giant trevally, and all manner of critters such as frogfish, shrimp and nudibranchs.


Just over half a mile (1kilometer) offshore at Ko Payan, Boulder City is an advanced site of large granite outcrops and huge boulders scattered across a sandy bottom. It leads round to Shark Fin Reef where further boulders and drop-offs create an exciting site. The brisk currents bring big pelagics such as mantas and whale sharks close in, and huge numbers of reef fish can also be spotted amongst the huge gorgonians and hard coral formations.

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The dive season of mid-October to mid-May coincides with the warmer, drier months on land, and air temperatures can reach the mid-80s (30°C) in April. The best time to spot mantas and whale sharks is between December and April.

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Travel Information 

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Several airlines fly from the US to Thailand’s Phuket International Airport (HKT) with a layover in Europe or Asia. Once in Phuket, it’s a 90-minute drive to Khao Lak to pick up the liveaboard.



The National Park is open from mid-October through to mid-May, and the dive season runs accordingly. Liveaboards generally visit for 4-nights or 7-nights, and some combine a longer trip with a visit to the nearby Surin Islands and Richelieu Rock. Boats tend to depart from Khao Lak on the mainland, but there are also departures from Ranong and Phuket.  

There is a wide range of liveaboard options, from modern motor yachts to a traditional junk. Trips range from laid-back and budget-friendly through to the more luxurious boats of the Aggressor fleet, and everything in between. Meals are often cooked by local chefs, and they are in a Thai style but cater towards western tastes.

Most boats will run 4 dives a day, including one dusk or night dive. There is also the option to snorkel between dives, and the possibility of a land-based excursion to explore the top-side wildlife.

Some Similan Islands trips also include diving in Myanmar, a unique and rarely visited destination.

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Most liveaboards will offer at least one land excursion to visit the islands’ tropical interiors. There are many nature trails and viewpoints, and some migratory birds found nowhere else in Thailand can be spotted. The white sandy beaches will take your breath away, and are perfect for an afternoon’s relaxation.

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  • Currency: Thai Baht (THB).
  • Language: Thai. 
  • Time Zone: Indochina Time (GMT+7).
  • Electricity:  230V. 

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Please contact us for the latest availability of the following boats: Diva Andaman, Similan Explorer, MV Hallelujah, Dolphin Queen, Deep Andaman Queen, MV Giamani, DiveRACEMV Oktavia, and MV Pawara.


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Call us today at +1-310-915-6677 or email us

And let us book your dream vacation!

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UNderwater images

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 Similan Islands Diving Similan Islands Diving

Similan Diving Similan Diving
 Similan Diving Similan Diving

MV Dolphin Queen MV Dolphin Queen 

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Reviews (2)


I went on a group trip to the Similan and Surin Islands in February of 2017 on the Junk liveaboard. The trip was a really great price, the dive liveaboard was clean and met basic necessity, and the food and the crew were really great. Overall, I would say that the wildlife in Thailand is very plentiful, although I would not say any of the dive sites particularly blew me away compared to other destinations except for a few: Richelieu Rock, Koh Bon, Hin Daeng, and Hin Muang.

Many of the sites on the Andaman side of Thailand had very interesting underwater structure -- huge boulder reef structures spotted with cup corals -- that were very unique to the dive destination, but not necessarily worth the price of the trip alone. However, the 4 dive sites I listed above were absolutely amazing, and these 4 dive sites alone made the entire trip to Thailand worth it, despite some of the other sites being slightly lackluster.

The pinnacles were covered in abundant soft corals that housed numerous nudibranchs playing hide and seek (spotting nudibranchs is one of my favorite scuba diving activities), surrounded by large schools of fish (both over the reef and in the blue), and sheltering abundant seahorses and cephalopods! I could've stayed on those locations to dive for all 10 days, they were so full of life and so vibrant and colorful.

To top it off, I stayed in Thailand for a few extra days to explore the area on land, and spent a few days traveling in Cambodia, as well. The region is so rich with culture and history -- combining these land activities with the beautiful diving made for one of the best trips for the price that I've taken! Don't forget to travel with your best dive buddies to make the trip irresistible:)

Visited on 03/2020 - Submitted on 03/24/2020

I enjoyed doing my Advanced course on a Similan Islands liveaboard over Christmas. The liveaboard itinerary had a wide variety of dive sites that were well-suited to the five course dives, which included fish identification, night, and drift dives in addition to the mandatory deep and navigation dives. It was my first liveaboard and I loved the easy routine of "dive, eat, sleep, repeat" and how many dives I was able to complete in such a short timespan. I saw a wide variety of marine life typical to the region, including leopard and reef sharks, stingrays, turtles, and loads of fish and macro life. I was not an experienced diver with only 6 logged dives at the time I embarked the boat, but I found the conditions suitable to my comfort level (aside from the night dive, which I swore I would never do again but am now a Night specialty instructor). We got to experience some topside activities, including a hike to a strangely perched boulder on a small island and I recall passing the beach from "The Beach", completely overcrowded with tourists and boats. If you're in Thailand, a liveaboard to the Similan Islands is a great way to get some dives in without breaking the bank or taking too much time. It's easy to get in and out of Phuket, where many boats depart from.

Visited on 12/2009 - Submitted on 04/26/2024


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